Download KEYWOFRDS: Ebola, Virus, Disease, Farm Animals Human Food

International Journal of Health and Psychology Research
Vol.4, No.3, pp.28-,37, October 2016
___Published by European Centre for Research Training and Development UK (www.eajournals.org)
―CAN EBOLA VIRUS DISEASE INFECT DOMESTIC AND FARM ANIMALS AND
AATHREAT FOR HUMAN BEING WHO HAS DIRECT CONTACT AND CONSUME
THEIR FOOD PRODUCTS?”
Alemayehu Worku (MSc, Animal science)
Arba Minch University, College of Agricultural Sciences, Department of Animal and Range
Sciences
ABSTRACT: Ebola virus disease (EVD) also known as Ebola hemorrhagic fever is a severe
contagious disease affecting humans, non-human primates and some domestic species (e.g.
pigs). While fruit bats are considered as a natural reservoir, the involvement of other species in
the EBOV transmission cycle is unclear, especially for domesticated animals. However Dogs and
pigs are so far the only domestic animals identified as species that can be infected with EBOV. In
2009 Reston-EBOV was the first EBOV reported to infect swine with indicated transmission to
humans; and a survey in Gabon found over 30% sero prevalence for EBOV in dogs during the
Ebola outbreak in 2001-2002. While infections in dogs appear to be asymptomatic, pigs
experimentally infected with EBOV can develop clinical disease, depending on the virus species
and possibly the age of the infected animals. In the experimental settings, pigs can transmit
Zaire-Ebola virus to native pigs and macaques monkeys; however, their role during Ebola
outbreaks in Africa needs to be clarified. In Africa, fruit bats are considered natural hosts and
reservoirs of the Ebola virus although Ebola outbreaks have been observed in chimpanzees,
gorillas, macaque monkeys and in some pigs in the Philippines and China. These latter animals,
like human beings, have been considered as “accidental hosts” and not reservoirs of the Ebola
virus. A fact sheet recently released by the World Health Organization (WHO) has proved
helpful in this regard, revealing that the Ebola virus is transmitted to people from animals and
subsequently spreads through the human population through person to person contacts. The risk
of infection among humans from animals may be reduced by avoiding contact with fruit bats or
monkeys etc. avoiding consumption of their raw meat and ensuring that all animal products are
thoroughly cooked before consumption. Animal handlers are advised to wear gloves and other
protective clothing. Significant issues about disease development remain to be resolved for
EBOV. Evaluation of current human vaccine candidates or development of veterinary vaccines
de novo for EBOV might need to be considered, especially if pigs or dogs are implicated in the
transmission of an African species of EBOV to humans.
KEYWOFRDS: Ebola, Virus, Disease, Farm Animals Human Food Products
INTRODUCTION
Ebola virus disease (EVD) is also known as Ebola hemorrhagic fever was first discovered in
1976 near the Ebola River in what is now the Democratic Republic of the Congo that affected
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International Journal of Health and Psychology Research
Vol.4, No.3, pp.28-,37, October 2016
___Published by European Centre for Research Training and Development UK (www.eajournals.org)
318 people and resulted in 280 deaths. Since then, outbreaks of Ebola among humans have
appeared sporadically in Africa. The virus and its five subtypes belong to a family of viruses
called Filoviridae; only four of the five subtypes have caused disease in humans (Jane H., 2012).
EVD is a severe contagious disease affecting humans, non-human primates and some domestic
species (e.g. pigs). It can be transmitted to humans through direct contact with blood, tissues,
body fluids and secretions from an infected animal or human, and from the handling of wild
animals hunted for food (WHO, 2014). The causative agent is classified in the genus Ebolavirus
of the Filoviridae family (Radford, D. et al, 2014).
The five known species in the genus Ebolavirus (EBOV) are: Zaire ebolavirus (ZEBOV); Sudan
ebolavirus (SEBOV); Bundibugyo ebolavirus (BEBOV); Reston ebolavirus (REBOV) and Taï
Forest ebolavirus (TEBOV). Their genomes can differ by 30-40%. Base on available evidence, it
is presumed that REBOV has a low pathogenicity or is non-pathogenic in humans whilst the
ZEBOV and SEBOV strains are known for their virulence and high case fatality rate (53 -90%)
in humans (Radford, D. et al, 2014).
Scientists believe Ebola spreads through zoonotic transmission- that is, coming from an animal.
The first patient of an Ebola outbreak is thought to be infected through contact with an infected
animal. From there, the virus can spread to other humans through direct contact with blood or
body fluids. Outbreaks often occur in healthcare settings (known as nosocomial transmission), as
patients seek treatment in facilities where appropriate infection-control may not be practiced.
The symptoms of Ebola are somewhat nonspecific at first. Within 2-21 days of exposure,
patients usually experience fever, headache, joint and muscle aches, sore throat, and weakness,
later followed by diarrhea, vomiting and stomach pain. Some patients also experience rash, red
eyes, hiccups and bleeding. From the onset of symptoms, Ebola can kill a patient within a matter
of days (Jane H., 2012).
In Africa, fruit bats are considered natural hosts and reservoirs of the Ebola virus although Ebola
outbreaks have been observed in chimpanzees, gorillas, macaque monkeys and in some pigs in
the Philippines and China. These latter animals, like human beings, have been considered as
―accidental hosts‖ and not reservoirs of the Ebola virus. Both the World Health Organization and
recent reports have suggested that the 2014 outbreak of Ebola can be traced to fruit bats in the
West Africa region. Guinea, where bat soup is a local delicacy, has reportedly banned the sale
and consumption of bat meat since the start of the outbreak (Naina, B. 2014). A fact sheet
recently released by the World Health Organization (WHO) has proved helpful in this regard,
revealing that the Ebola virus is transmitted to people from animals and subsequently spreads
through the human population through person to person contacts (WHO, 2014).
Ebola is introduced into the human population through close contact with the blood, secretions,
organs or other bodily fluids of infected animals. In Africa, infection has been documented
through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and
porcupines found ill or dead or in the rainforest. Ebola then spreads in the community through
human-to-human transmission, with infection resulting from direct contact (through broken skin
or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected
people, and indirect contact with environments contaminated with such fluids. Burial ceremonies
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International Journal of Health and Psychology Research
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___Published by European Centre for Research Training and Development UK (www.eajournals.org)
in which mourners have direct contact with the body of the deceased person can also play a role
in the transmission of Ebola. Men who have recovered from the disease can still transmit the
virus through their semen for up to 7 weeks after recovery from illness (WHO, 2014).
Given its high case fatality rates, prevention is critical. Efforts to control Ebola virus infection
among domestic animals may include routine cleaning and disinfection with sodium
hypochlorite or other detergents in monkey and pig farms, and quarantining the premises and
restricting animal movement during suspected outbreaks. Essentially, an active animal
surveillance system is required as an early warning mechanism as infections among especially
pigs and monkeys are known to precede outbreaks in humans.
The risk of infection among humans from animals may be reduced by avoiding contact with fruit
bats or monkeys etc. avoiding consumption of their raw meat and ensuring that all animal
products are thoroughly cooked before consumption. Animal handlers are advised to wear gloves
and other protective clothing.
Objectives

To investigate whether the Ebola virus disease can infect domestic or farm animals based
on the different study conducted so far.
LITERATURE REVIEW
What is Zoonosis Disease?
Zoonotic diseases are infectious diseases that are naturally transmitted from vertebrate animals to
humans and vice versa. They are caused by all types of pathogenic agents, including bacteria,
parasites, fungi, viruses and prions. Although they have been recognized for many centuries,
their impact on public health has increased in the last few decades due to a combination of the
success in reducing the spread of human infectious diseases through vaccination and effective
therapies and the emergence of novel zoonotic diseases (Wang and Crameri, 2014).
As zoonosis is by definition transmissible between animals and humans, it is not surprising that
most are also transmissible between wildlife and domestic animals. Transmission depends upon
contact (direct or indirect) between livestock, domestic animals and people and
transmission opportunities are subject to various, sometimes opposing drivers. The
unprecedentedly large human population and the associated increases in demand for land, food
(and use of natural resources is the root cause of increased transmission opportunities (Grace and
Johns, 2011).
The World Health Organization (WHO)/Food and Agriculture Organization of the United
Nations (FAO)/World Organization for Animal Health (OIE) joint consultation on emerging
zoonotic diseases held in Geneva, May 2004, defined an emerging zoonosis as ‗a zoonosis that is
newly recognized or newly evolved, or that has occurred previously but shows an increase in
incidence or expansion in geographical, host or vector range‘ (WHO, 2004). Emerging zoonotic
diseases have potentially serious human health and economic impacts and their current upwards
trend is likely to continue. The last 30 years have seen a rise in emerging infectious diseases in
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International Journal of Health and Psychology Research
Vol.4, No.3, pp.28-,37, October 2016
___Published by European Centre for Research Training and Development UK (www.eajournals.org)
humans and of these over 70% are zoonotic (Jhones et al; 2008, Woolhouse et al 2005).
Zoonotic infections are not new. They have always featured among the wide range of human
diseases and most, e.g. anthrax, tuberculosis, plague, yellow fever and influenza, have come
from domestic animals, poultry and livestock. However, with changes in the environment,
human behavior and habitat, increasingly these infections are emerging from wildlife species.
The WHO and most infectious disease experts agree that the source of the next human pandemic
is likely to be zoonotic, and wildlife is emerging as the primary source. Many zoonoses from
wildlife, including avian influenza and rabies, are well established, while others have only
recently emerged or have only recently been linked to wildlife reservoir species. One example of
the latter is the Ebola virus, which, after decades of research, was recently linked to cavedwelling bats in Africa (Leroy. et al 2008 and Li. et al 2005).
Emerging Disease
While each of us come and go about our daily business, there is a secret hidden war that is
occurring all around us. It is a war between humanity, and the various populations of
microorganisms all around us. There are approximately 1,407 organisms (fungi, bacteria,
parasites, protozoa and viruses) that can infect humans. Roughly 58% of these are considered to
be animal diseases, and most of these have an Old World origin as a result of man‘s development
of agriculture and animal domestication. In addition, there are now some 177 pathogens
considered to cause newly emerging or reemerging diseases.
The term emerging disease defines an infectious disease that has newly appeared in a population,
or is rapidly increasing in incidence or geographic range. During the past 30 years some 41 new
infectious organisms or strains have jumped from their animal hosts into humans. This is typified
by the period of 2012 to 2014, with the appearance of the Middle East Respiratory Syndrome
Coronavirus (MERS-CoV), the lethal Bas-Congo rhabdovirus that causes hemorrhagic fever and
kills within a few days, the large Sierra Leone-Liberia- Ebola outbreak, the continuing Kasai
Oriental Province outbreaks of human Monkeypox, and cases of African Chikungunya virus in
Florida with an epidemic currently underway in Puerto Rico.
One significant emerging infection is the Ebola Virus. The Ebola virus is nothing more than a
collection of seven different proteins surrounding a strand of nucleic acid which contains the
instructions for making copies of those proteins once the virus enters a human cell. As with all
viruses known to science, the Ebola virus borders on the definition of what is considered a living
organism.
Can Domestic and farm animals shed Ebola and transmit to human?
What animals have been shown to shed Ebola virus?
Field studies and epidemiological surveys in Africa have demonstrated widespread antibody
prevalence to Ebola viruses in fruit bats suggesting that fruit bats may be natural hosts for
EBOV. When bats and other vertebrate species were experimentally inoculated, only bats
became infected and shed virus in feces without showing any clinical signs. Monkeys are not
considered as natural hosts because of their high sensitivity to the virus and their high mortality
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International Journal of Health and Psychology Research
Vol.4, No.3, pp.28-,37, October 2016
___Published by European Centre for Research Training and Development UK (www.eajournals.org)
rate when infected. Only mammals (for example, humans, bats, monkeys, and apes) have shown
the ability to become infected with and spread Ebola virus.
The role of pigs in EVD epidemiology is unclear. Pigs infected with ZEBOV showed mild
clinical signs, and were able to transmit the virus to non-human primates (Weingartl et al 2012).
There is no evidence that domestic animals play an active epidemiological role in the
transmission of the disease to humans, although field studies are non-existent.
2.3.2. Can pets become infected with Ebola virus?
A study in 2005 identified an increasing seropositivity to ZEBOV in dogs sampled in regions of
Africa that were proximate or distant from known ZEBOV outbreaks – the closer the dog was to
the outbreak region, the more likely it was to have antibodies directed against ZEBOV.
However, the authors failed to detect either RNA (by RT-PCR) or viral antigen (by viral
isolation, although viral isolation failed in the positive control samples as well). The authors
concluded that ZEBOV could induce an immune response in dogs, but could not determine if
dogs could shed the virus.
Guinea pigs, goats, and horses remain subclinical or develop mild clinical signs after
experimental infection, but Ebola virus infection has never been observed in these species in the
wild.
The Ebola virus can be found across the animal kingdom, from bats and birds to pigs and
porcupines. But there is a difference between having a disease and transmitting it to another
animal or another species. That‘s at the heart of a controversial move by Spanish health
authorities, who have obtained a court order to euthanize the dog belonging to a nurse who
contracted the Ebola virus in Madrid, saying that available scientific knowledge suggests dogs
can transmit the virus to humans. But how much do we know about which animals can catch and
transmit the deadly virus? (Naina, B. 2014)
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International Journal of Health and Psychology Research
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___Published by European Centre for Research Training and Development UK (www.eajournals.org)
Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention (CDC), said in
a news conference on Tuesday that ―we know in rural areas of Africa, Ebola can infect
mammals. In fact, that‘s how it spreads, from probably bats to animals living in the forest, people
hunting the animals.‖ Ebola has to date been found in many bush animals, including bush pigs,
rodents, porcupines and forest-dwelling antelope. Any infected carcasses could spread the virus
to hunters or to anyone who eats bush meat (Naina, B.2014).
Can Dogs get Ebola?
Yes. After the 2002 Ebola outbreak in Gabon, researchers from the US Centers for Disease
Control and Prevention (CDC) discovered that many of the animals that came into direct contact
with disease, later tested positive for it. It is believed the dogs contracted the virus by scavenging
for infected bush meat, but it could also have been transmitted through contact with the bodily
fluids of an infected human. However the virus had no harmful effect on the canines as they
showed no symptoms and did not become ill or die.
However up to the recent date, there is no documented case of Ebola spreading to people from
dogs or dogs to people, and only one study, carried out by the CDC, looks at whether dogs can
get Ebola at all. This research into the prevalence of Ebola-virus antibodies in dogs from regions
of Gabon affected by the 2001–2002 outbreak showed that ―dogs can be infected by Ebola virus‖
but exhibit no symptoms and the infection eventually clears (Naina, B.2014).
The researchers concluded that ―dogs could be a potential source of human Ebola outbreaks and
of virus spread during human outbreaks,‖ but they did not test their hypothesis that human
infection could occur through licking, biting or grooming. Instead, the study assumed dogs
would transmit the infection in the same way as other animals observed in experiments; those
animals excreted viral particles (in saliva, urine, feces) for a short period before the virus was
cleared. David Moore, an expert in infectious diseases from the London School of Hygiene and
Tropical Medicine, said that since no dogs showed symptoms of the Ebola virus ―there is
absolutely no evidence to support a role for dogs in transmission.
The study also suggests that differences in behavior and diet of pet dogs may alter risks in Ebola
transmission. Whereas most dogs in Western Europe are fed dog food, many of the dogs studied
in Gabon scavenged for their food, eating small dead animals that could have exposed them to
the virus.
On the other had dogs are not subclinical carriers of Ebola virus and there also not be any
information on how long can a dog be infected with Ebola Virus. In this regard recent study
indicates that there is no evidence currently that dogs can carry and shed Ebola virus. No virus
has ever been isolated from a dog. Also Since there is no evidence that dogs can become infected
with Ebola virus, there is no way to estimate duration of infectivity (which would involve viral
replication and shedding). Dog is no seropositive for anti-Ebola antibodies infected and can then
transmit the virus. Seroconversion only requires that antigen be presented by antigen-presenting
cells to lymphocytes. Infection requires invasion of host cells, replication, and shedding.
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International Journal of Health and Psychology Research
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___Published by European Centre for Research Training and Development UK (www.eajournals.org)
Can Birds get Ebola?
There is limited data about the prevalence of Ebola in birds but a 2002 study from Purdue
University found that the Ebola virus closely resembles the structure of several bird viruses. This
means birds may be able to spread the virus to humans. Head researcher David Sanders said
―while bird transmission of Ebola is by no means certain, the resemblance among all these
viruses should encourage health officials to be on guard for it.
Can Pigs Get Ebola?
Until 2009 no one knew that pigs could carry Ebola, because they show no symptoms of the
disease. Three years after a case in the Philippines showed Ebola transmission between pigs and
farmers, Canadian scientists found that apparently healthy pigs could pass on the most deadly
strain of Ebola (the Zaire-Ebola virus) to monkeys without direct contact. In pigs, the virus
mainly affects the lungs and airways, which means they can spread the virus through the air via
small droplets (this does not mean Ebola is suddenly an airborne virus like SARS). However,
Gary Kobinger who led the study said ―we still don‘t know if pigs are playing any role in the
natural transmission or ecology of Ebola virus in Africa.‖ (Naina, B., 2014).
Can Domestic Animals Gets Ebola?
Various studies carried out in the 1990s found that some animals (including guinea pigs, goats
and horses) showed no or mild symptoms when infected with Ebola during experiments. The
virus has never been observed in these species in the wild, but like pigs and dogs, these animals
do not appear to get ill or die from Ebola.
Relatively little research has been carried out into the existence of Ebola in many other animals.
It is thought that domestic cats are probably immune to it since the virus has not yet been found
in any wild felines in Africa.
Some Facts about Ebola Transmission
Can pets transmit Ebola virus to people or other animals?
There is no evidence that domestic species, including dogs, can or ever have, transmitted Ebola
virus to humans or other animals. Some investigators have questioned the role of dogs in
transmission where no obvious source was identified in an outbreak; however, these outbreaks
occur in regions where exposure documentation is limited, incomplete or inaccurate. Therefore,
such hypotheses are speculative at best. On the other hand, rigorous investigation of potential
canine infections in field situations is virtually non-existent.
Is Ebola transmitted via aerosol?
There is no evidence that Ebola virus is transmitted by aerosol, water or food. In two separate
experimental studies—one with monkeys and the other pigs and monkeys—the authors suggest
an airborne possibility of transmission. However, this route of transmission was not confirmed
and other means of transmission were not ruled out. (Jaax et al, 1995, Weingartl et al 2012).
What should be done with a pet in the home of an Ebola patient?
CDC recommends that public health officials, in collaboration with a veterinarian, evaluate the
pet‘s risk of exposure to the virus (close contact or exposure to blood or body fluids of an Ebola
patient). Based on this evaluation as well as the specific situation, local and state human and
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International Journal of Health and Psychology Research
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___Published by European Centre for Research Training and Development UK (www.eajournals.org)
animal health officials will determine how the pet should be handled. Currently, a dog exposed
to an infected health worker in Texas, is being quarantined at a decommissioned military base. A
veterinarian who is caring for the animal of an Ebola patient or the animal of someone who has
been in contact with an Ebola patient should contact their state health department for guidance.
What is the evidence about fomite (including fur) transmission and survival times of the
virus?
While there is no evidence that the virus can be transmitted on the fur or saliva of dogs, there is
some evidence that fomite-associated transmission might occur (Jaax N et al, 1995). Therefore,
the CDC advises that the most prudent course of action is to keep pets away from people who
have been exposed to, or are infected with, Ebola virus.
Can Ebola virus survive in the environment?
Ebola viruses are encapsulated viruses and therefore sensitive to desiccations, detergents and
disinfectants. They do not survive for long in the environment (hours, rather than days or weeks),
and can be inactivated with exposure to many disinfectants. According to the Centers for Disease
Control and Prevention (CDC): ―The role of the environment in transmission has not been
established. Limited laboratory studies under favorable conditions indicate that Ebola virus can
remain viable on solid surfaces, with concentrations falling slowly over several days. In the only
study to assess contamination of the patient care environment during an outbreak, virus was not
detected in any of 33 samples collected from sites that were not visibly bloody...There is no
epidemiologic evidence of Ebola virus transmission via either the environment or fomites that
could become contaminated during patient care (e.g., bed rails, door knobs, laundry). However,
given the apparent low infectious dose, potential of high virus titers in the blood of ill patients,
and disease severity, higher levels of precaution are warranted to reduce the potential risk posed
by contaminated surfaces in the patient care environment.‖
Should we worry?
Scientists have yet to confirm Ebola‘s natural host—the animal that naturally holds the infection
and is a primary source for the spread of the disease—but transmitting the virus is a different
issue. Since ―lethal disease has only thus far been seen in humans and primates and a few species
of wild animals, it would appear that the main route of transmission is human to human contact,‖
says John Blackwell, President of the British Veterinary Association, an organization that often
issues advice when animal-related diseases could affect the general public(Naina, B., 2014).
He adds that the course of disease in dogs and their role in transmission is not yet known, but ―it
would be a sensible precaution‖ to observe strict quarantine measures for animals in contact with
a confirmed or suspected case of Ebola. As the Madrid nurse and her husband continue to
campaign to save their dog from being put down, it remains to be seen what precautions the
Spanish government will take in order to contain the spread of the Ebola virus.
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International Journal of Health and Psychology Research
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___Published by European Centre for Research Training and Development UK (www.eajournals.org)
CONCLUSIONS
Based on the review of different scenario so far with regard to infection of domestic and farm
animals as well as their role in transmitting the disease as a host animal, the following
conclusions are drawn

In Africa, fruit bats are considered natural hosts and reservoirs of the Ebola virus, while
the involvement of other species in the EBOV transmission cycle is still unclear, especially for
domesticated animals.

Ebola outbreaks have been observed in chimpanzees, gorillas, macaque monkeys and in
some pigs in the Philippines and China. These latter animals, like human beings, have been
considered as ―accidental hosts‖ and not reservoirs of the Ebola virus.

Dogs and pigs are so far the only domestic animals identified as species that can be
infected with EBOV. While infections in dogs appear to be asymptomatic, pigs experimentally
infected with EBOV can develop clinical disease, depending on the virus species and possibly
the age of the infected animals.

Guinea pigs, goats, and horses remain subclinical or develop mild clinical signs after
experimental infection, but Ebola virus infection has never been observed in these species in the
wild.

In 2009 Reston-EBOV was the first EBOV reported to infect swine with indicated
transmission to humans; and a survey in Gabon found over 30% sero prevalence for EBOV in
dogs during the Ebola outbreak in 2001-2002.

In the experimental settings, pigs can transmit Zaire-Ebola virus to naive pigs and
macaques monkeys; however, their role during Ebola outbreaks in Africa needs to be clarified.

A fact sheet recently released by the World Health Organization (WHO) has proved
helpful in this regard, revealing that the Ebola virus is transmitted to people from animals and
subsequently spreads through the human population through person to person contacts.

The risk of infection among humans from animals may be reduced by avoiding contact
with fruit bats or monkeys etc. avoiding consumption of their raw meat and ensuring that all
animal products are thoroughly cooked before consumption. Animal handlers are advised to
wear gloves and other protective clothing.

Significant issues about disease development remain to be resolved for EBOV.
Evaluation of current human vaccine candidates or development of veterinary vaccines de novo
for EBOV might need to be considered, especially if pigs or dogs are implicated in the
transmission of an African species of EBOV to humans.
REFERENCES
Jane H., 2012. Did Scientists Just Discover a Cure for Ebola? The Disease daily magazine,
published on June 22, 2012.
Naina Bajeka. 2014. Ebola and domestic animals/Can Dogs (And Other Animals) Get Ebola_
TIME.html
WHO (2014). WHO Statement on the Meeting of the International Health Regulations
Emergency Committee regarding the 2014 Ebola outbreak in West Africa.
Radford, D. and J.Scott Weese 2014. Ebola and domestic animals/01 Veterinary Considerations
for Ebola Virus Outbreaks - VeterinaryPartner.com - a VIN company.
36
International Journal of Health and Psychology Research
Vol.4, No.3, pp.28-,37, October 2016
___Published by European Centre for Research Training and Development UK (www.eajournals.org)
Allela L, Bourry O, Pouillot R, Delicat A, Yaba P, Kumulungui B, Rouquet P, Gonzalez J-P,
Leroy EM. Ebola virus antibody prevalence in dogs and human risk. Emerg. Infect. Dis.
2005;11(3):385-390.
Jaax N, Jahrling P, Geisbert T, Geisbert J, Steele K, McKee K, et al. Transmission of Ebola virus
(Zaire strain) to uninfected control monkeys in a biocontainment laboratory. Lancet.
1995;346:1669–71.
Weingartl HM, Embury-Hyatt C, Nfon C, Leung A, Smith G, & Kobinger G. Transmission of
Ebola virus from pigs to non-human primates. Scientific Reports Nov. 15, 2012.
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